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kb:turbulence [2014/07/22 17:02] – [Turbulence Model in ENVI-met] enviadmin | kb:turbulence [2022/04/04 19:26] (current) – [Turbulence Model in ENVI-met] enviadmin | ||
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===== Turbulence Model in ENVI-met ===== | ===== Turbulence Model in ENVI-met ===== | ||
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+ | ---- this information is outdated --- | ||
ENVI-met uses the so-called 2-equation Turbulence Kinetic Energy (TKE) Model to predict the turbulence in the air. \\ | ENVI-met uses the so-called 2-equation Turbulence Kinetic Energy (TKE) Model to predict the turbulence in the air. \\ | ||
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As the result of the TKE-ε equation Km (via Ke and directly) is used as input data for the next calculation cycle, there is a non-linear feedback loop between the turbulent exchange coefficient and the TKE-ε equation. Once Km begins to be unstable, the TKE-ε equation system will get unstable too, producing even more unstable Km's in the next loop.\\ | As the result of the TKE-ε equation Km (via Ke and directly) is used as input data for the next calculation cycle, there is a non-linear feedback loop between the turbulent exchange coefficient and the TKE-ε equation. Once Km begins to be unstable, the TKE-ε equation system will get unstable too, producing even more unstable Km's in the next loop.\\ | ||
- | To avoid numerical problems, several mechanisms have been introduced in ENVI-met making the turbulence model more reliable: | ||
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- | * [[Two-Step Calculation Loops (Initialisation)]] | ||
- | * [[Intelligent Troubleshooting via Relaxation]] | ||
- | * [[Range Limiting]] | ||
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